DESCRIPTION: The overall goal of this proposal is to elucidate the precise role of the nuclear RARs in mediating the growth response of human breast cancer cells to retinoic acid. The specific aims of this proposal are: 1) to determine if growth suppression of RA-sensitive cells can be modulated by changing the RAR profile in these cells; 2) to elucidate the molecular basis for the altered RAR profile in RA- resistant breast cancer cells; 3) to identify RAR/RXR tanscriptional targets which mediate the RA-dependent suppression of breast cancer cell growth; and 4) to examine the molecular mechanism by which these RAR/RXR transcriptional targets regulate RA-mediated growth suppression.